I recently read some of Marc Boney's articles on vedic astrology. He's an excellent teacher and I can only recommend reading his works. However, I've noticed that at times he is taking great liberties in terms of birth time. He says that with the given birth time the chart makes no sense and so he rectifies it and adds a few more minutes here and takes a few minutes away there. He's a student of K.N. Rao who was a staunch supporter of the official Lahiri Ayanamsa. Just as an example, Boney rectified Queen Elizabeth II birth time because the official time gave an Ascendant that didn't explain her life story. And he is correct, of course. However, if he would have used a different Ayanamsa, he wouldn't have had that problem in the first place. And what are the chances that the royal family gets their times of birth wrong? So that seemed a bit suspicious. It seemed to be more a problem of an incorrect Ayanamsa value than an incorrect birth time. So I thought I should do some actual research on my own.
Sometimes a change of Ayanamsa doesn't give any changes in the birth chart in terms of planets in houses or signs. Aynamsa sensitive are divisional charts and Dashas. So that would be a good place to test Ayanamsas. But the problem here is that even though with different Ayanamsas giving very different placements in divisional charts and timing sequences in Dashas, because vedic astrology is so rich in methods and techniques, there's always a way to explain just anything somehow and as a result, just any Ayanamsa works more or less. Which makes comparing Ayanamsas rather difficult. So I decided to be really strict and don't use karakas, special lagnas or aspects and only the placements of dasha lords and lords of their sub and sub-sub periods in the respective houses and/or lagnas in their respective divisional charts. That will give less optimal results, of course, and it's not expected that any Ayanamsa will reach 100% accuracy. But it allows to actually compare values.
There are roughly 5 groups of Ayanamsas:
1) Tropical
2) The Revati group (offset about 20 degrees) - Usha-Shashi, Sassanian, Hipparchus
3) The Galactic center group (offset about 22 degrees) - Raman, Yukteshwar, Brand
4) The Chitra Group (offset about 24 degrees) - Lahiri, Krishnamurti
5) The Babylonian group (offset about 25 degrees) - Fagan
And there are also 3 different timing systems for Dashas:
1) tropical years (365.25 days)
2) savana years (360 days)
3) tithi years (354 days)
I am testing one Ayanamsa from every group with all 3 timing methods. Events will include marriage, career, children and death so there are about 15 data points per chart on average and I will make use of D1, D7, D9 and D10 charts.
So far I've tested it with charts of 12 famous people (all Rodden A or AA rating). The results are quite surprising. After only a dozen charts there's already a pattern showing. The only Ayanamsa group that is consistently above 50% accuracy is the Revati group. All others are all over the place (between 25% and 75% accuracy) and seem to be leveling out at around 50%. So in that sense on average Lahiri is as good as Yukeshwar/Raman, Fagan or Tropical. Hipparchus, however, seems to be leveling out at 60%. In terms of timing systems, there isn't a real difference in the end.
I'd be grateful if you guys have some suggestions re famous people, preferably with Rodden AA rating, lots of data points in terms of marriage, children, career - like Liz Taylor (several marriages, several children, several oscars/golden globes)
Cheers!
Sometimes a change of Ayanamsa doesn't give any changes in the birth chart in terms of planets in houses or signs. Aynamsa sensitive are divisional charts and Dashas. So that would be a good place to test Ayanamsas. But the problem here is that even though with different Ayanamsas giving very different placements in divisional charts and timing sequences in Dashas, because vedic astrology is so rich in methods and techniques, there's always a way to explain just anything somehow and as a result, just any Ayanamsa works more or less. Which makes comparing Ayanamsas rather difficult. So I decided to be really strict and don't use karakas, special lagnas or aspects and only the placements of dasha lords and lords of their sub and sub-sub periods in the respective houses and/or lagnas in their respective divisional charts. That will give less optimal results, of course, and it's not expected that any Ayanamsa will reach 100% accuracy. But it allows to actually compare values.
There are roughly 5 groups of Ayanamsas:
1) Tropical
2) The Revati group (offset about 20 degrees) - Usha-Shashi, Sassanian, Hipparchus
3) The Galactic center group (offset about 22 degrees) - Raman, Yukteshwar, Brand
4) The Chitra Group (offset about 24 degrees) - Lahiri, Krishnamurti
5) The Babylonian group (offset about 25 degrees) - Fagan
And there are also 3 different timing systems for Dashas:
1) tropical years (365.25 days)
2) savana years (360 days)
3) tithi years (354 days)
I am testing one Ayanamsa from every group with all 3 timing methods. Events will include marriage, career, children and death so there are about 15 data points per chart on average and I will make use of D1, D7, D9 and D10 charts.
So far I've tested it with charts of 12 famous people (all Rodden A or AA rating). The results are quite surprising. After only a dozen charts there's already a pattern showing. The only Ayanamsa group that is consistently above 50% accuracy is the Revati group. All others are all over the place (between 25% and 75% accuracy) and seem to be leveling out at around 50%. So in that sense on average Lahiri is as good as Yukeshwar/Raman, Fagan or Tropical. Hipparchus, however, seems to be leveling out at 60%. In terms of timing systems, there isn't a real difference in the end.
I'd be grateful if you guys have some suggestions re famous people, preferably with Rodden AA rating, lots of data points in terms of marriage, children, career - like Liz Taylor (several marriages, several children, several oscars/golden globes)
Cheers!